In some countries such as Japan, an electricity charge is calculated based on a basic charge, an electric energy charge generated according to a used power amount, a renewable energy levy, and the like. Among them, the basic charge may be calculated based on the use amount every 30 minutes when the amount of power usage is the largest in a year. Thus, when it is desired to lower the basic charge, it is necessary to perform a peak cut that reduces the amount of power usage in a (peak) period of time in which the amount of power usage is the largest in the year. With such a background, there has been proposed a power control apparatus that executes power saving, discharge using a power storage device, or the like during a period in which the amount of power usage is likely to peak and performs the peak cut to reduce a basic charge.
When the peak cut operation is performed by the discharge of the power storage device, it is general to set a threshold for power supplied from a power system and perform control such that a peak of the supplied power within a predetermined period (for example, 30 minutes) does not exceed the threshold.
However, if the threshold is too high, the discharge from the power storage device is hardly performed so that the frequency of obtaining the effect of the peak cut decreases. On the other hand, if the threshold is too low, the power storage device is discharged more than necessary, and the storage capacity of the power storage device becomes empty during the period of time that needs to be subjected to the peak cut so that it is difficult to perform the discharge and the peak cut. Thus, it is necessary to set an optimum threshold in accordance with the storage capacity of the power storage device.
In addition, if the power storage device is frequently discharged to unnecessarily perform the peak cut despite the fact that dates on which the peak cut needs to be performed are inherently limited, deterioration of the power storage device is accelerated because the number of times of charge/discharge of the power storage device increases. In addition, if a battery is occupied to perform battery control for the peak cut, it is difficult to use the battery as an emergency power supply for virtual power plant (VPP) or business continuity planning (BCP), or the like, other than the peak cut operation.